Turbine starting mechanism



raph '15,, 1953 A. D. ZAKARIAN TURBINE STARTING MECHANISM 3 Sheets-Sheetl ---IIIIII Filed March 15, 1951 INVENTOR D. ZAKARIAN ATTORNEYS 2,65il91m Eta y 1951-} A. D. ZAKARKAN TURBINE STARTING MECHANISM 3Sheets-Sheet 2 Filed March 15, 1951 WWW -IT W IET TQ W\ em, fi W525 A.D. ZAKAREAN 25L 1 TURBINE STARTING MECHANISM Filed March 15, 1951 5Sheets-Sheet 3 I VENTOR ARSHAM D. ZAKARIAN y 4, 3- JR Patented Sept. 15,1953 TURBINE STARTING MECHANISM A i-sham D. Zakarian, Del Mar, Calif.,assignor to Solar Aircraft Company, San Diego, Calif., a corporation ofCalifornia Application March 13, 1951, Serial N 0. 215,252

11 Claims.

This invention relates to starting means for turbo-compressor powerplants and has for its general object and purpose to provide manuallyoperable means for eliminating load on the turbine compressor assemblyuntil it is brought to a predetermined starting speed. Another objectresides in providing a gas turbine, having a scroll connected with theoutlet of a combustion chamber and a compressor having a scrollconnected with an air intake port of the combustion chamber, with valvemeans operable to close communication between the compressor and thecombustion chamber during the starting period.

A more detailed object of the present invention resides in providing theoutlet duct of the compressor scroll of a gas turbine with a shut-01fvalve disk having an external operating lever to be selectively closedto unload the compressor and turbine rotors during starting of the gasturbine and accessible to an operator standing beside the gas turbine.

Still another object of the present invention resides in providing a gasturbine with a simple, inexpensve, valve means selectively operable tounload the compressor and turbine rotors and condition the gas turbinefor manual starting.

With the above and other objects in view, the invention comprises theimproved starting aid for turbo-compressor units as will hereinafter bemore fully described, illustrated in the accompanying drawings andsubsequently incorporated in the subjoined claims.

In the drawings, wherein is disclosed one simple and practicalembodiment of the invention and in which similar reference charactersdesignate corresponding parts throughout the several views:

Figure 1 is a side elevation partially in section of a gas turbinedriven pump unit incorporating the starting aid of the presentinvention;

Figure 2 is a top plan view'of Figure 1 with parts shown in section andother parts broken away to more clearly illustrate the nature and use ofthe present invention;

Figure 3 is an end elevation;

Figure 4 is a detailed vertical section taken on the line 4-4 of Figure2, illustrating the details of the present invention.

For the purpose of illustrating one practical embodiment of the presentinvention, in the accompanying drawings, there is shown a gas turbinecomprising a turbine unit I!) and an air compressor unit l2, each of theradial flow type, combined in a unitary assembly and having the rotorsl4 and 16 (Figure 1) respectively, suitably fixed to one end of aturbine shaft l8 connected to a gear box unit l9 adapted to drive anysuitable mechanism. Gear box unit IS, in a preferred use of the presentinvention, forms a part of a gas turbine driven, portable, high capacitypump unit fully described and claimed in the copending application ofLeon R. Wosika and Arsham D. Zakarian, Serial No. 216,282, filed March19, 1951, and entitled Pump and Power Plant Assembly. For the purpose ofthe present invention, it will sufiice to state that the compressor unit12 is provided with an air conducting scroll 20 the circular outlet duct2| of which is connected with the air intake port 24 of a combustionchamber 22 fully described and claimed in the copending application ofGrant B. Hodgson, Serial No. 215,- 298 filed on even date herewith andentitled Gas Turbine Combustion Chamber. It is, of course, to be clearlyunderstood that the present invention may be embodied in any gas turbineconstruction and that its utility is not confined to either the portablepump or combustion chamber structures of the aforementionedapplications.

Turbine unit [0 is provided with a simlar scroll 28 having its inlet endconnected with the outlet end of combustion chamber 22. Fuel is sprayedinto the mixing head 30 of combustion chamber 22 through a nozzle 28mounted in the chamber 22. Head 30, as clearly described in aforesaidHodgson application, produces an intimate mixture of the fuel particlesand air for ignition by a spark plug mounted in the Wall of thecombustion chamber at a suitable location indicated at 32 in Figure 2 ofthe drawings. Since the combustion chamber construction and air and fuelmixing means 30 forms no part of the present invention further detaileddescription thereof is not believed necessary here.

The other end of turbine shaft I8 is drivingly coupled to a powertake-off shaft 34 of gear box 20. In the illustrated construction, shaft34- is mounted in the horizontal plane of turbine shaft I8 andsubstantially at right angles thereto and the coupling means comprises aring gear 36 fixed to power take-off shaft 34 and in constant mesh witha pinion 38 secured to the end of shaft I8 and journalled in a suitableanti-friction hearing assembly 40.

The power take-01f shaft 34 may conveniently drive a centrifugal pump,partially illustrated at 22, which is suitably mounted together with theturbine and compressor units l0 and I2 in a supporting frame structure44 to form a pump unit for use as portable fire fighting equipment onshipboard, the drainage of excavations, or for other purposes. Theturbine compressor assembly and pump unit are preferably of small sizeand comparatively light weight, the frame with the turbine andcompressor units, gear box, and pump structure being easily movable fromplace to place.

While the starting means for the turbo-compressor unit may take anydesired form, the illustrated unit embodies a shaft 46 journalled at itsends in suitable bearings 48 on the frame structure 64. To each end ofthis shaft, a suitable folding operating crank 56 is fixed. A largediameter sprocket 52 is also fixed to shaft 46 and is con-, nected bysprocket 54 with a small diameter sprocket 56 journalled on one endof astub shaft 58 together with a large diameter sprocket 60. If desired thehub portions of sprockets 60 and 56 may be integrally formed. Shaft 58is suitably fixed in a bracket 59 on the gear box casing I9. Sprocket 68is connectedby drive chain 62 with the drive sprocket 64 of a one-wayoverrunning clutch device of conventional type contained in housing 66and mounted on one end of the power take-off shaft 34 and through whichrotation is transmitted to the power take-off shaft 34 at an increasedspeed relative to the manually rotated shaft 46.

In the illustrated structure, the sprocket and gear ratios are such thatthe shaft it, upon manual operation of cranks 56, will be rotated atapproximately %3 of the normal operating speed of the gas turbine, thegear 36 and the pinion 38 serving to step up the speed of turbine shaft18 and the rotors l4 and I6 serving as fly wheels. The gearing 36--38,when the turbine is driving, transmit rotation of the power take-offshaft 34 at a comparable reduced speed.

In order to substantially eliminate load on the turbine compressor unitduring starting, the present invention contemplates manually operablebutterfly valve 68 mounted in the outlet duct 2| of the compressorscroll for rotation around an axis, preferably in a plane containing theaxis of the combustion chamber, constituting a diameter of duct 21. Suchmounting of valve 68 assures a minimum restriction of the inlet passageand whatever division of the air stream results is in a vertical planecontaining the axis of the combustion chamber thereby assuring asubstantially equal flow of air lengthwise of the combustion chamber.

While the journals for valve 68 may be formed in any suitable manner,the illustrated embodiment provides diametrically opposed integralbosses 69 of substantially greater thickness than the wall of duct 2|formed near the outlet end of duct 2|. These bosses have aligned borestherethrough for rotatably receiving a valve supporting and operatingshaft 'H, the upper end of which protrudes beyond its adjacent boss toreceive an operating lever 12 on which a round base 13 is integrallyformed.

The bores in bosses 69 provide axially extending journal surfaces ofsubstantial area to assure a mounting for valve 68. The round base 13 oflever 12 prevents marring of the face of boss 69 and holds shaft llagainst axial displacement when valve attachment screws 14 are removed.

A pin 15, Welded to the lever 12, is notched at its upper end to supportone end of a spring 16, the other end of which is secured to anL-shaped. bracket I! mounted on the duct 2 I.

A downwardly projecting wedge-shaped stop 18 is welded to the lowersurface of the base 13 and is adapted in one position to engage the flatshoulder 19 formed at one side of boss 69 and. in its other positionfiat shoulder formed on boss 69. The shoulders 19 and 80 are positionedon boss 69- so that the sprin 16 urges the lever and stop 18 against oneor the other depending upon which side of the center of shaft H, pin 15lies. In one position, the valve 68 will occupy its full open position.When the lever and stop 18 are moved away from the open position theopposite radial edge of stop 18 will engage the shoulder -80 at theopposite side of shaft 1 I when the fully closed position of the valveis reached. It will be noted that in this latter position, the axis ofspring 16 passes slightly beyond the axis of shaft H. The spring 16 isthus effective to hold the valve in either the closed or open position.

Upon closing valve 68, communication between the compressor and thecombustion chamber 22 is cut off so that the compressor vanes on rotor16 will move in still air,- the major portion of the air being simplycarried around by the compressor vanes after a slight head has beenbuilt up in the scroll 20. The compressor [2 thus does practically nouseful work, after equilibrium has once been established. This is alsotrue of the turbine rotor. When equilibrium is established the air inthe turbine rotor vane passages merely revolves with the rotor. Thus, ineffect, the closing of the valve 68 practically eliminates the load onthe compressor turbine assembly and allows it to be brought to speed inan unloaded condition, in a manner similar to an inertia starter.

As soon as the turbine is brought to starting speed, fuel from anysuitable source is supplied to the nozzle 28, valve 68 is opened, andthe fuel mixing with the air supplied by the compressor forms acombustible mixture in combustion chamber 22. This combustible mixtureis ignited by the spark plug which is energized momentarily through anysuitable means, such as magneto 61 supported by a suitable supportbracket 10 mounted on shaft 58 and bracket 59 and energized by therotation of cranks 50, shaft 46 and sprockets 52, 56, 60, and thesprocket of the one way clutch in housing 66.

After initial combustion is effected, cranking is continued to A; ratedspeed, and the turbine, due to the temperatures produced by the productsof combustion, becomes self sustaining and the products of combustiondischarged through scroll 26 from combustion chamber 22 against thevanes of the turbine rotors l4 drive the compressor, gear box, and pumpunit in well known manner. When the drive is then transmitted by theturbine through gear 36 and pinion 38 to power take-off shaft 34, theoverrunning clutch unit releases the driving connection with themanually operated sprocket chains so that the starting mechanism remainsstationary.

Vfhile valve means 68 may be of any suitable type, a conventionalbutterfly type valve is believed preferable. It will also be understoodthat the driving couple between the turbine shaft l8 and power take-offshaft 34 as above described is merely suggestive and in certaininstances the two shafts might be arranged in coaxial alignment andconnected by a conventional type planetary gear drive or otherequivalent means.

From the above description, it will be seen that the present inventionprovides manually operable means minimizing the manual or other startingeffort by the substantial elimination of rectroactive load forces on thegas turbine unit and assuring rapid establishment of the effective powertransmitting operation of the gas turbine. Since the several parts of myinvention are of standard structural form, the improved starting meanswill not materially increase the overall production cost of suchturbo-compressor units and expense incident to the necessary replacementof parts is reduced to a minimum.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiment is therefore to be considered in all respects as illustrativeand not restrictive, the scope of the invention being indicated by theappended claims rather than by the foregoing description, and allchanges which come within the meaning and range of equivalency of theclaims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States LettersPatent is:

1. In combination with a turbo-compressor power plant including a singlecompressor and gas turbine unit, a single combustion chamber having anoutlet passage leading to said turbine and an air intake passage leadingto said compressor, and auxiliary means for applying cranking torque tosaid turbo-compressor power plant; a compressor turbine unloader valvedisposed between the compressor and said combustion chamber in saidintake passage selectively operable during operation of said auxiliarymeans to close communication between said compressor and said turbinethereby unloading said power plant and adapting it for free rotationwhereby said power plant may be quickly brought up to starting speedwith a minimum of cranking effort.

2. The combination defined in claim 1 wherein said valve comprises abutterfly valve.

3. The combination defined in claim 1 wherein said intake passage is ofcircular configuration in cross section and said valve comprises abutterfly valve journalled in the opposite Walls of said passage forrotation around an aXis constituting a diameter of said passage.

4. The combination defined in claim 3 wherein the axis of rotation ofsaid butterfly valve lies in a plane containing the axis of saidcombustion chamber.

5. A starting valve assembly for unloading a turbo-compressor powerplant having a compressor scroll terminating in a single air outlet ductto facilitate starting of said turbo-compressor and comprising aperturedjournal bosses formed on said duct adjacent its outlet end indiametrically opposed relation; a valve support shaft journalled in saidapertured bosses and having one end protruding outwardly from itsadjacent boss; a valve disk removably secured to said shaft between itsjournalled portions and having an area equal to the internal area ofsaid duct whereby said valve, in its passage closing position, closessaid passage preventing fluid movement in said duct and said compressorto effectively unload the compressor and turbine to permit said powerplant to be easily and quickly brought up to starting speed; and anoperating lever secured to the protruding end of said shaft forselectively moving said valve to its closed and open positions.

6. For use in a turbo-compressor power plant having a single compressoroutlet passage leading to a single combustion chamber; a starting valvefor unloading the compressor and turbine rotors during manual crankingand starting of the power plant comprising valve supporting structuredisposed along said passage; a valve body supported by said supportingstructure and adapted when closed to prevent communication between saidcompressor and combustion chamher through said passage whereby fluid insaid compressor and duct will be stalled to effectively unload saidcompressor and said turbine will be starved and also effectivelyunloaded; and valve operating means accessible from the exterior of saidpassage for moving said valve to closed position during cranking of saidpower plant and opening said valve when said power plant reachesstarting speed.

7. The combination defined in claim 6 where in said valve body comprisesa relatively thin disk mounted for selective rotation in said passagefrom one to the other of its open or closed positions.

8. The combination defined in claim 6 wherein the axis of rotation ofsaid disk coincides with a diameter of said passage.

9. The combination defined in claim '7 wherein the axis of rotation ofsaid disk lies in a plane containing the axis of said combustion chamberto thereby assure substantially equal flow of fluid axially from saidpassage to the axially extending areas of said combustion chamber.

10. In combination with a single compressor and gas turbine assembly asingle combustion chamber having an outlet port connected with theturbine and an air inlet port connected with the compressor, a powershaft connected through a gear transmission to a driven member, andmanually operable means for transmitting starting torque to said powershaft through said gear transmission: a starting aid comprising a valvein the compressor outlet to close communication between the compressorand combustion chamber to stall fluid movement therebetween andeffectively unload the compressor and turbine during the startingperiod.

11. In combination with a power plant having turbine-compressor units; aconduit having a portion adapted to carry all of the gas passing fromthe compressor unit to the turbine unit, combustion means operativelyconnected to said conduit portion for combusting said gas to providemotive force to be delivered to said turbine through said conduit, andmovable valve means mounted within said conduit for selectively openingand closing said conduit to fiuid flow between said compressor and saidturbine units whereby when valve is in closed position fluid movementbetween said compressor and said turbine unit is stalled and the turbineand compressor units are effectively unloaded and can be easily broughtup to a high starting speed.

ARSHAM D ZAKARIAN.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,262,195 Noack Nov. 11, 1941 2,365,551 Hermitte Dec. 19, 19442,390,959 Pfenninger Dec. 11, 1945 2,547,660 Prince Apr. 3, 1951

